But look at it like this:
Southend would have been attractive for all passengers who
- don't like to transit through a behemoth like LHR or LGW, (Then fly from STN)
- have business to do east of central London, (Then fly from STN)
- resent using Ryanair, (Then fly EZY or 4U)
- have been waiting for a LCY link from CGN for a long time (Not sure why SEN compares to LCY much more than the other LON airport currently served from CGN other than the general size)
I think it's only common sense for Stobart Air as a new operation to play it safer if you like for the time being.